1. Field of the Invention
The present invention relates to serum-based vaccines that are substantially free of non-host albumin and processes for preparing and using the same. More specifically, the present invention relates to the inventive concept of vaccines that prevent or substantially reduce post-vaccination adverse systemic reactions associated with adjuvanted vaccine regimens.
2. Brief Description of the Prior Art
It is known in the art that vaccination of animals with vaccine regimens involving the use of adjuvants can cause adverse systemic reactions. The vaccine regimen can comprise administration of inactivated vaccine containing an adjuvant. Alternately, the vaccine regimen can comprise administration of a modified live vaccine and an inactivated vaccine containing an adjuvant. Illustratively, most feline vaccine regimens comprise administration of a vaccine containing a modified live organism concomitantly with a vaccine containing an inactivated organism and an adjuvant. Associated with these vaccination regimens are adverse systemic post vaccination reactions. For instance, the use of feline leukemia vaccines (FeLV) can cause post-vaccination reactions including excess salivation, vomiting and diarrhea. See the monograph on FEL-O-VAX Lv-K® vaccine in the Compendium of Veterinary Products, page 486, Third Edition, 1995-1996. The adverse systemic reactions include anaphylaxis, hypersensitivity and atypical reactions such as vomiting and diarrhea.
Contrary to the present inventive concept, the prior art has attributed the above named systemic reactions to the presence of adjuvants, endotoxins, cellular debris residue, high concentration of modified live viruses or high antigenic mass. Dodds, Vaccine Safety and Efficacy Revisited: Autoimmune and Allergic Diseases on the Rise, Vet. Forum, pp 68-71, May, 1993 noted an increase in post-vaccination autoimmune and allergic diseases. Dodds has postulated that the increase is due to the immunological burden on susceptible animals exposed to a combination vaccine containing modified live organisms and adjuvanted, killed bacterins administered at the same time (as the diluent). Dodds also postulated that the immunological burden is produced by the effect of the modified live organisms.
The search for safe and effective vaccines has been limited by the paucity of information regarding the source of the problem of post-vaccination reactions. There is no indication in the literature or otherwise that teaches that these systemic reactions could be caused by an interaction of non-host albumin with an adjuvant. Indicating the contrary is the prevalent use of non-host albumin in the presence of adjuvants. Dogs receive adjuvanted rabies vaccine at the same time that they receive modified live combination vaccines containing non-host albumin. Cats receive adjuvanted FeLV vaccine in a vaccine regimen comprising the concomitant administration of a modified live vaccine containing non-host albumin. Also, combinations of albumin and adjuvants are commonly used in the art to evaluate the effectiveness of adjuvants. Albumin, generally in the form of Bovine Serum Albumin (BSA), is formulated with various adjuvants and each formulation is injected into non-bovine animals. The animals are bled at some later date and their sera are measured for antibody responses to BSA. The animals showing the best antibody responses are considered to have received the most effective adjuvants. Prince et al, U.S. Pat. No. 4,164,565 discloses the use of non-host albumin as a stabilizer in vaccines. Wiedmeier et al., Pediatric Research, Vol. 3, page 262-267, September, 1987 discloses reactivity in mice produced by immunization with Bordetella pertussis combined with Bovine albumin. Notably, Wiedmeier et al teaches that the cause of reactivity is the pertussis toxin in combination with albumin.
To help reduce the systemic reactions, one can purify vaccines to remove components thereof which presumably cause the systemic reactions. Animal vaccine preparations are typically purified by conventional methods such as filtration, diafiltration or centrifugation to remove components such as cells and cellular debris. Other methods of purification that yield highly purified antigens are seldom employed because they are cost prohibitive in the preparation of animal vaccines. Illustrative of the other methods of purification is column chromatography, including ion exchange chromatography, molecular sieve chromatography and hydrophobic interaction chromatography. Moreover, highly purified antigens are difficult to adjuvant with the commonly used adjuvants because they are not effective enough to stimulate a protective response with purified antigens. At any rate, these purification methods were not effective for removing non-host albumin from vaccines or precursors thereof.
The art has not attributed the cause of systemic reactions to the presence of adjuvants and non-host albumin. Certainly, the art has not attributed the cause of systemic reactions to the presence of non-host albumin in the vaccine regimen involving the use of adjuvants.
By the present invention, it has been realized that the presence of non-host albumin in an adjuvanted vaccine or vaccine regimen can cause systemic reactions. By the present invention, there is provided a novel serum-based adjuvanted vaccine or vaccine regimen that is substantially free of non-host albumin and a method of preparing the same.